Rcd Required By Thai Code?

[doglover]

We are renting a house in a gated community in Khon Kaen which we stay at during the week so our kids can attend a decent school. The project is no more than five years old and there is a Safe-T-Cut brand CU upstairs and downstairs. I was surprised to find that there is no adjustable main RCBO installed in either CU. The mains must be spliced in the attic as each panel has only two mains wires.

Is it not required by Thai electrical code to have a RCD? Or is that only for TT installations?

Also there is no MEN link in the CU's. Is that not also typical for "big city" distribution networks?

Fortunately the receptacles are on dedicated circuits and there are spare slots in the CU's. So I can just swap out the receptacle circuit MCB's for RCBO's.

Downstairs there will be appliances on the circuit so I was thinking of installing a 10mA RCBO, yet this is also the area most likely to have one of our children stick something in a receptacle. Upstairs I would be installing a 5mA as there are no appliances.

Now it's time for constructive criticism.

[Crossy]

The 'code' such as it is requires front-end RCD protection and 3-pin outlets on all new installations.

This is widely ignored but MEA/PEA may not certify and connect if it's not done.

Same goes for MEN, it should be that way but again it's largely ignored. Note that the Thai MEN connection is similar to that used by the NEC, i.e. the incoming neutral passes via the ground bar on it's way to the main breaker.

Now for your proposal: If we were in the West, no argument, but TiT

Assuming you currently have no RCD protection at all I would stick an RCBO (stand alone Safe-T-cut) on the front end of each panel.

The problem you will have if you decide to go with RCBOs in place of the MCBs will be isolating the neutrals. Thai sparks borrow neutrals all over the place and it only needs one loan neutral for your RCBO to refuse to stay 'on'.

[Forkinhades]

Yes required by law.

IMO you should install a main RCD at the front end of both CUs set at 30mA

Dont worry about the MEN connection, it shoud only be done on the supply side anyway. If it was done on the consumer side, your RCD protection would not work.

If you went for individual RCBO's you will struggle to find 10mA or even 5mA, in any case both would be (IMO) too sensitive. 30mA is fine

Forky

[Forkinhades]

me and x y posting at the same time agian

[Crossy]

Great minds think alike Forky

[bankruatsteve]

The OP said he already had Safe-T-Cut boxes. So, why would there not be the main RCD? I thought that's the only way they come.

[Forkinhades]

The OP said he already had Safe-T-Cut boxes.  So, why would there not be the main RCD?  I thought that's the only way they come.

The OP states that he has a safety cut brand.

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

[doglover]

Came back empty handed from my trip to Global House. The only individual RCBO's they have are Schneider brand and incompatible with this CU. (good point about the borrowed neutrals)

I found it surprising that I could buy an entire 8 way safe-t-cut brand CU with RCBO main breaker for the same price as a stand alone RCBO 30mA breaker. There is not enough room to fit the safe-t-cut brand RCBO main inside the existing CU's.

I think I'll look for a GFCI receptacle and swap it out with the first receptacle in the circuit.

[Crossy]

The OP said he already had Safe-T-Cut boxes. So, why would there not be the main RCD? I thought that's the only way they come.

Safe-T-Cut make consumer units without RCD/RCBO protection too http://www.safe-t-cut.com/Product.htm

Confusing as h3ll for Joe Public who of course assume that a unit marked Safe-T-Cut is an RCBO.

[Crossy]

I think I'll look for a GFCI receptacle and swap it out with the first receptacle in the circuit.

Note that simply replacing the first outlet on the radial with an RCD outlet will NOT protect the other outlets on the circuit unless the RCD outlets have a pass-through function.

Check the instructions carefully, post scans here if in doubt.

[doglover]

^^^

I had just realized that and logged back on but too late. My logic center was working in the Canadian region where radials are not used.

[doglover]

With the recommendation of 30mA being sufficient RCD protection I have come up with the following as the cheapest option I could find. Purchased and installed a 25A (didn't have a 20A) Haco ELB in series with the receptacle circuit MCB. Time will tell if the circuits neutral has been borrowed but so far so good.

This is a temporary solution and rather mickey mouse but I have an agreement with the landlord of not drilling any holes in the walls. I also did not want to spend the baht required for a stand alone RCBO for the mains as I can't see needing it after our lease is up. And yes the wiring is ugly as it's temporary.

The size of the Haco ELB worked out well vertically as it is just slightly bigger than the hole in the CU cover so I could jam it in and have it hold itself in place. Horizontally it was narrower than two MCB slots so there is a small gap there unfortunately. Also the switch of the Haco is longer than the stock MCB's so the transparent cover does not completely close .

But for 450 baht it works for me.

[Crossy]

Looks like a good solution DL, for 450 Baht you could leave it behind for the next occupant when you leave

[doglover]

Well that was short lived. <deleted> borrowed a neutral for the gate lights! And here I thought with a 100+ housing project from a semi-respectable name would make my 450 baht a sure bet! Live and learn.

At least I can try the receptacle circuit upstairs for free.....